I buy 6 CDs for $6.99. How much change do I get from $50?

Please does it mean one CD $6.99 or 6 CDs total $6.99? Cheers!

As it reads, it means $6.99 for all 6 CDs.

If the writer meant $6.99 for each CD, he/she should have written it this way:
I buy 6 CDs for $6.99 each. How much change ...